On the operation of machines powered by quantum non-thermal baths

Wolfgang Niedenzu, David Gelbwaser-Klimovsky, Abraham G. Kofman, Gershon Kurizki

Research output: Contribution to journalArticlepeer-review


Diverse models of engines energised by quantum-coherent, hence non-thermal, baths allow the engine efficiency to transgress the standard thermodynamic Carnot bound. These transgressions call for an elucidation of the underlying mechanisms. Here we show that non-thermal baths may impart not only heat, but also mechanical work to a machine. The Carnot bound is inapplicable to such a hybrid machine. Intriguingly, it may exhibit dual action, concurrently as engine and refrigerator, with up to 100% efficiency. We conclude that even though a machine powered by a quantum bath may exhibit an unconventional performance, it still abides by the traditional principles of thermodynamics.

Original languageEnglish
Article number083012
JournalNew Journal of Physics
Issue number8
StatePublished - Aug 2016


  • Heat engine
  • Non-passivity
  • Open quantum system
  • Quantum thermodynamics

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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